Problem: On the way to school, Karen became fixated on the puzzle game on her phone!

<image>

The game is played as follows. In each level, you have a grid with n rows and m columns. Each cell originally contains the number 0.

One move consists of choosing one row or column, and adding 1 to all of the cells in that row or column.

To win the level, after all the moves, the number in the cell at the i-th row and j-th column should be equal to gi, j.

Karen is stuck on one level, and wants to know a way to beat this level using the minimum number of moves. Please, help her with this task!

Input

The first line of input contains two integers, n and m (1 ≤ n, m ≤ 100), the number of rows and the number of columns in the grid, respectively.

The next n lines each contain m integers. In particular, the j-th integer in the i-th of these rows contains gi, j (0 ≤ gi, j ≤ 500).

Output

If there is an error and it is actually not possible to beat the level, output a single integer -1.

Otherwise, on the first line, output a single integer k, the minimum number of moves necessary to beat the level.

The next k lines should each contain one of the following, describing the moves in the order they must be done:

  * row x, (1 ≤ x ≤ n) describing a move of the form "choose the x-th row". 
  * col x, (1 ≤ x ≤ m) describing a move of the form "choose the x-th column". 



If there are multiple optimal solutions, output any one of them.

Examples

Input

3 5
2 2 2 3 2
0 0 0 1 0
1 1 1 2 1


Output

4
row 1
row 1
col 4
row 3


Input

3 3
0 0 0
0 1 0
0 0 0


Output

-1


Input

3 3
1 1 1
1 1 1
1 1 1


Output

3
row 1
row 2
row 3

Note

In the first test case, Karen has a grid with 3 rows and 5 columns. She can perform the following 4 moves to beat the level:

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In the second test case, Karen has a grid with 3 rows and 3 columns. It is clear that it is impossible to beat the level; performing any move will create three 1s on the grid, but it is required to only have one 1 in the center.

In the third test case, Karen has a grid with 3 rows and 3 columns. She can perform the following 3 moves to beat the level:

<image>

Note that this is not the only solution; another solution, among others, is col 1, col 2, col 3.

Solution (in CPP):

Solution:
#include <bits/stdc++.h>
using namespace std;
const int N = 105;
const int oo = 1e9;
int g[N][N], n, m;
int col[N];
vector<pair<int, int> > ans;
pair<int, int> get(int val) {
  for (int i = 1; i <= m; ++i) {
    if (g[1][i] < val) return {oo, val};
  }
  memset(col, 0, sizeof(col));
  ans.clear();
  int ret = val;
  for (int i = 1; i <= m; ++i) col[i] = g[1][i] - val;
  ans.push_back({1, val});
  for (int i = 2; i <= n; ++i) {
    int mn = oo, mx = -oo;
    for (int j = 1; j <= m; ++j) {
      if (g[i][j] < col[j]) return {oo, val};
      mn = min(mn, g[i][j] - col[j]);
      mx = max(mx, g[i][j] - col[j]);
    }
    if (mn != mx) return {oo, val};
    ans.push_back({i, mn});
    ret += mn;
  }
  for (int i = 1; i <= m; ++i) {
    ans.push_back({-i, col[i]});
    ret += col[i];
  }
  return {ret, val};
}
int main() {
  scanf("%d %d", &n, &m);
  for (int i = 1; i <= n; ++i) {
    for (int j = 1; j <= m; ++j) {
      scanf("%d", &g[i][j]);
    }
  }
  pair<int, int> ret = {oo, -1};
  for (int i = 0; i <= 500; ++i) ret = min(ret, get(i));
  if (ret.first == oo) {
    printf("-1\n");
    return 0;
  }
  get(ret.second);
  printf("%d\n", ret.first);
  for (auto u : ans) {
    if (u.first < 0) {
      for (int i = 1; i <= u.second; ++i) printf("col %d\n", -u.first);
    } else {
      for (int i = 1; i <= u.second; ++i) printf("row %d\n", u.first);
    }
  }
  return 0;
}